51 results about "Celestial sphere" patented technology

This disclosure provides a method for segmenting a star catalog. The method includes: acquiring a target star catalog file corresponding to a target celestial sphere, the target star catalog file including observation data of M celestial bodies in the target celestial sphere; dividing the target celestial sphere into N sub-regions and N region numbers corresponding to the N sub-regions based on a predetermined maximum segmentation level K; determining the number of celestial bodies in each region represented by each of the N region numbers based on the observation data of the M celestial bodies in the target star catalog file, obtaining a result determining the number of N celestial bodies; and segmenting the target star catalog file according to the matching result between the result determining the number of N celestial bodies and a predetermined segmentation threshold T, determining multiple star catalog subset files corresponding to the target star catalog file. This disclosure also provides an apparatus, device, and storage medium for segmenting star catalogs.

The invention belongs to the technical field of industrial automation, and particularly relates to a Healpix-based star catalogue homogenization segmentation and evaluation method. The method comprises the following steps: S1, acquiring original star catalogue data, and determining Healpix grid level parameters based on an expected subdivision degree of a user; s2, calculating a Healpix pixel index number of each celestial body by adopting a Healpix algorithm based on celestial sphere coordinates of each celestial body in a celestial sphere equator coordinate system contained in the original star catalogue data; s3, constructing a blank star catalogue, and constructing a homogenized star catalogue based on the celestial body set extracted by the sampling strategy and the Healpix pixel index number corresponding to each celestial body contained in the celestial body set; and S4, constructing a Uscore evaluation model, performing Uscore scoring on the homogenized star catalogue by using the Uscore evaluation model, and evaluating the uniformity of each celestial body in the homogenized star catalogue based on the Uscore score. According to the invention, an objective and quantifiable comparison reference is provided for the effects of different homogenization methods.

This application relates to the field of orbital dynamics design and simulation technology, and provides a method and apparatus for free transformation between spatial coordinate systems for solar system spacecraft design and simulation. This method transforms the position and velocity of different coordinate systems to the celestial coordinate system for origin transformation, and then rotates to the target coordinate system. This allows position and velocity to be arbitrarily transformed between coordinate systems included in the coordinate transformation model library. Furthermore, when expanding to a new coordinate system, only the transformation function between the new coordinate system and the co-centered celestial coordinate system is needed, without having to calculate the transformation functions between the new coordinate system and all other coordinate systems separately. This achieves effective organization of scattered coordinate system transformation relationships, facilitating the design and simulation of spacecraft missions and reducing the workload generated by transformations between multiple spatial coordinate systems.

Methods and apparatus for specular surface mapping in which a camera detects reflections of a light source from a specular surface. The detected light sources may be projected onto a celestial sphere as virtual point sources. True positive observations should be tightly clustered on the celestial sphere; thus, false positives may be identified and removed. Specular surface information may then be determined from clusters of the virtual point sources on the celestial sphere. The clusters of virtual point sources on the celestial sphere may be identified and used to identify a surface as a specular surface. The clusters may also be used to extract other information regarding the specular surface, including but not limited to distance to and extent of the specular surface.

The invention provides an autonomous visual navigation method for on-orbit remote identification and target tracking of a satellite. The method comprises the following steps: acquiring an original image observation star point position; extracting a navigation star library in a view field range according to the camera optical axis direction and the camera view field; constructing an observation triangle by using the observation star points, and calculating angular distance information between the observation star points; searching the angular distance of the navigation star triangle in the star database, matching the angular distance with the angular distance information of the observation triangle, determining an observation star point, and calculating an attitude conversion matrix between the celestial coordinate system and the camera coordinate system; according to the matrix, back-projecting star points in the star catalogue into the spacecraft image, and matching and deleting the star points; performing continuous multi-frame target detection to determine a spacecraft target; the method comprises the following steps: acquiring a mass center position of a target in a spacecraft image, solving an azimuth angle and a pitch angle of a current spacecraft in a celestial body, performing navigation positioning on the spacecraft target, realizing remote point target tracking, and performing back projection verification on the image in the tracking process.

This invention discloses a method and system for space target detection and self-calibration photometry in spaceborne star field imaging. The method includes the following steps: acquiring the raw telemetry data stream from the satellite in spaceborne star field imaging mode, and reconstructing a two-dimensional raw image sequence; performing self-calibration radiometric correction, background noise modeling, multi-frame registration, source parameter extraction, and space target discrimination on the raw image sequence to obtain the corresponding stellar background, space targets, and single-frame artifacts; constructing a standard star candidate set and fitting a mapping model from standard star pixel coordinates to celestial coordinates; converting the pixel coordinates of the space target to the corresponding celestial coordinates; performing photometric zero-point fitting and space target photometry operations; and outputting structured space target observation results. This invention relates to the field of space target observation technology. By introducing multi-frame self-calibration radiometric correction, inter-frame geometric registration and multi-frame consistency discrimination, and robust photometric zero-point fitting, reliable observation of spaceborne space targets is achieved.

The application provides a simplified attitude distribution cooperative control method for a directed communication leader-follower spacecraft formation, which comprises the following steps: firstly, describing the simplified attitude motion of the spacecraft in a unit celestial coordinate system, and converting the simplified attitude motion into a translation of the terminal point of a pointing vector on a unit celestial sphere; secondly, designing a distributed cooperative virtual control quantity under a directed communication topology according to the consistency theory, so as to ensure that the pointing vector of the follower spacecraft converges to a fixed pointing direction in the inertial space determined by the pointing vector of the leader spacecraft, and then calculating an ideal angular velocity vector of the follower spacecraft according to the virtual control quantity; thirdly, taking the difference between the angular velocity vector of the follower spacecraft and the ideal angular velocity vector as a sliding mode variable, and designing a sliding mode surface; and finally, designing a distributed cooperative control law for the follower spacecraft based on a super-twisting second-order sliding mode control method. The application can ensure that the pointing vector of the follower spacecraft in the directed communication formation converges to the pointing vector of the leader spacecraft fixed in the inertial space under a disturbance environment, and reduces the communication amount of the formation.

A solar apparent motion demonstration instrument relates to a teaching demonstration appliance. The instrument can visually demonstrate the sun apparent motion trail and the sunrise and sunset moments on the earth at any latitude and any day. The instrument is composed of a support, a celestial sphere shell, a horizon circle hemisphere shell and a horizon observation time measuring ring. The horizon ring hemisphere shell is arranged in the celestial sphere shell, and the celestial sphere shell and the observation horizon time measuring ring are arranged on the bracket; the celestial sphere shell is a transparent hollow sphere; the horizon ring hemisphere shell is a transparent hollow hemisphere, and the large circular surface of the horizon ring hemisphere shell represents the horizon ring; a small amount of water is injected into the celestial sphere shell, and the horizon ring hemisphere shell is placed into the celestial sphere shell, so that the horizon ring hemisphere shell floats; the celestial sphere shell is connected with the upper end point and the lower end point of the support round frame through rotating shafts. And the observation ground time measuring rings are fixed on two sides of the support circular frame. The vertical rotation instrument can change the geographic latitude of an observer, and the transverse rotation instrument can simulate the weekly-day apparent motion of the sun.

The invention relates to a method (PREF) for referencing at least one artificial satellite (SAT) in a star catalogue (CTG), comprising a step of positioning at least one star projected onto a celestial sphere (SC). The method comprises: a step (E10) of obtaining coordinates (Oqd,) of an observed position of the at least one artificial satellite (SAT) and orbit parameters (TLE) of the at least one artificial satellite (SAT); a step (E50) of projecting the satellite (SAT) onto the celestial sphere (SC) in a viewing direction determined from the orbital parameter (TLE) and the observation position; -a step (E80) of recording the coordinates of the satellites (SAT) projected onto the celestial sphere (CS) into the star catalogue (CTG), in which the coordinates of the fixed star and of the at least one artificial satellite (SAT) are expressed in the same geocentric reference frame, referred to as fixed star catalogue reference frame.

This invention belongs to the field of industrial automation technology, and particularly relates to a method for uniform segmentation and evaluation of star catalogs based on Healpix. The method includes: S1: acquiring original star catalog data and determining the Healpix grid level parameters based on the user's desired subdivision level; S2: calculating the Healpix pixel index number of each celestial body in the original star catalog data using the Healpix algorithm, based on the celestial coordinates of each celestial body in the celestial equatorial coordinate system; S3: constructing a blank star catalog and building a uniform star catalog based on the set of celestial bodies extracted by a sampling strategy and the corresponding Healpix pixel index numbers of each celestial body contained in the set; S4: constructing a U_score evaluation model and using the U_score evaluation model to score the uniform star catalog, and evaluating the uniformity of each celestial body in the uniform star catalog based on the U_score score. This invention provides an objective and quantifiable benchmark for comparing the effects of different uniformization methods.

The invention belongs to the technical field of astronomical science popularization, and discloses an astronomical science popularization explanation device, which controls the movement of a telescope through a motor to ensure that the telescope can position and observe a target celestial body; the motor driving system ensures that the telescope can execute pointing and tracking according to user requirements; the laser indication system adopts a high-speed horizon theodolite design, is provided with a variable-color laser and is used for indicating a target celestial body in real time according to the output of the knowledge explanation system; the embedded hardware system comprises a master controller, a motor driver, a sensor and the like, and is responsible for overall operation and control of the device; the invention ensures the safe and reliable operation of the system. The laser transmitter provides a clear and stable laser beam, and the pointing mechanism can perform accurate adjustment, so that the laser beam is aligned with a target celestial body. And the celestial navigation and positioning module continuously updates the understanding of the system on the celestial sphere to realize the real-time tracking of the moving celestial body. And the safety protection mechanism protects the user and the equipment from potential hazards possibly caused by laser use.

The application discloses a kind of scientific research data analysis platform for fast radio burst, including data management module: for the structured, standardized, standardization management fast radio burst related scientific research data;Fast radio burst searching module: for searching fast radio burst in radio telescope observation data, and intercept fast radio burst sample storage in database;Fast radio burst sample analysis module: based on astronomical data analysis algorithm component, fast radio burst sample is in-depth analyzed, and analysis result is transmitted to visual module;Visual module: based on real galaxy distribution constructs 3D celestial sphere model, and fast radio burst data and analysis result are shown on the corresponding position of celestial sphere model.The application provides fast radio burst data acquisition, management and sharing function, constructs rich standardization data analysis capability, realizes analysis result visualization, greatly improves data acquisition and analysis efficiency, promotes astronomical achievement sharing, accelerates scientific research achievement output.

1. Name of the product in this design: Digital Planetarium (Hun Tian Xin Yun). 2. Intended use of this design: for use in buildings. 3. The key design feature of this product is its shape. 4. The image or photograph that best illustrates the design's key features: the front view. 5. The bottom surface of this product is a part that is not easily seen or cannot be seen during use, so the bottom view is omitted.

The application relates to a space target local retrieval and identification method, and belongs to the cross field of space situation awareness, space dynamics and high-performance databases. The steps comprise the following steps: multi-source TLE orbit data and service attribute fusion pretreatment; multi-feature fusion dynamic decision tree adaptive time step allocation based on orbit period, eccentricity and task type; the HEALPix equal-area celestial sphere gridding algorithm is introduced to reduce the three-dimensional continuous observation space to a discrete one-dimensional grid identifier, and a lightweight space-time key-value pair is reconstructed in combination with discrete time slicing; a high-concurrency space-time inverted index is reconstructed by multi-process lock-free sandbox streaming writing and database kernel-level aggregation deduplication; a fast initial screening of candidate targets is realized by constructing an anti-time-space aliasing dynamic safety margin expansion search area; and high-precision target accurate matching identification. The application realizes fast retrieval and high-confidence identification of a large number of space targets with a constant-level time complexity, and significantly improves the real-time response capability of a space situation awareness system.

The invention provides a method, system and medium for satellite orbit extrapolation through GPU acceleration, and the method comprises the steps: generating a plurality of satellite initial orbits according to an STK simulation scene, and enabling the satellite initial orbits to be used for the initial orbit input of each thread of the GPU acceleration orbit extrapolation; constructing a mechanical model of the satellite and a motion differential equation of the satellite according to the motion characteristics of the satellite; loading the initial orbit data of each satellite, the mechanical model data and the time-space conversion parameter data to a GPU; unifying a space-time system of an initial orbit epoch and a mechanical model, converting coordinated world time into centroid dynamics, and converting the space system into a geocentric celestial coordinate system; constructing a global function by utilizing CUDA (Compute Unified Device Architecture), and transmitting a parallel computing task to a task calling unit of a GPU (Graphics Processing Unit) by utilizing the global function; and loading the orbit calculated by the task calling unit in the GPU into the CPU, and carrying out overlapping comparison on the orbit and the orbit of each satellite in the STK. The method can meet the processing requirements of a large number of satellites and mass orbit measurement data.

The invention discloses a false star filtering and star map recognition method based on multi-sky-area parallelism, which is applied to autonomous attitude determination of a star sensor and comprises the following steps: constructing a multi-sky-area parallelism index database of a whole celestial sphere, dividing a whole celestial sphere space represented by a unit spherical surface, and generating a plurality of candidate sky-area sets which cover the whole celestial sphere and are allowed to be overlapped with one another; the method for extracting star pattern features based on the discretized radial angular distance comprises the following steps: extracting position parameter information of observation star points based on star map data acquired by a star sensor, and constructing a radial feature vector for representing a local spatial distribution relationship of fixed stars for each observation star point in a star map; performing feature matching of the multi-day-area parallel star mode feature vectors, and calculating a matching evaluation index based on the feature matching; and a final star map recognition result is obtained based on iterative screening recognition and false star elimination. And outputting a final star map recognition result for subsequent attitude calculation. The invention further discloses a corresponding system, electronic equipment and a computer readable storage medium.

The invention provides a direction adjustment assembly, imaging equipment and a polar axis alignment method, and relates to the field of astronomical photography. The direction adjusting assembly comprises an azimuth angle adjusting mechanism and an elevating angle adjusting mechanism. The first end of the azimuth angle adjusting mechanism is connected with the second end of the elevation angle adjusting mechanism; the second end of the azimuth angle adjusting mechanism is connected with the supporting mechanism; the first end of the elevating angle adjusting mechanism is connected with the celestial sphere pointing adjusting device; the azimuth angle adjusting mechanism and the elevating angle adjusting mechanism are configured to drive the celestial sphere to point to the target rotating shaft of the adjusting device to move based on the movement of the azimuth angle adjusting mechanism in the azimuth angle direction and the movement of the elevating angle adjusting mechanism in the elevating angle direction. By using the orientation adjusting assembly provided by the embodiment of the invention, the azimuth angle and the elevation angle of the celestial sphere orientation adjusting device of the imaging equipment can be adjusted through the cooperation of the azimuth angle adjusting mechanism and the elevation angle adjusting mechanism, and the automatic and efficient epipolar axis of the celestial sphere orientation adjusting device is realized.

This invention relates to an on-orbit calibration method for the micro-variations of intrinsic parameters of a high-precision star sensor optical system, belonging to the field of high-precision on-orbit calibration technology for spacecraft. First, using the ground-calibrated intrinsic parameters of the optical system as initial values, the relationship between various coordinate systems and the angular distance model of the star sensor points is combined to establish the equality between the angle of the direction vector in the star sensor camera coordinate system and the angle of the navigation star in the celestial coordinate system. Then, based on this, and considering the characteristic that the angular distance between observed stars and the angular distance of the navigation star remain unchanged after environmental changes, a calibration model for the micro-variations of the intrinsic parameters of the star sensor optical system used in this invention is established. Finally, the extended Kalman filter (EKF) algorithm is used to calibrate the micro-variations of the intrinsic parameters of the optical system. After the micro-variation calibration is completed, the initial intrinsic parameter values ​​are added to obtain the intrinsic parameters of the optical system after environmental changes.

The utility model provides a device for simulating and drawing solar apparent moving tracks at different latitudes and different times, and belongs to the technical field of teaching aids. The device comprises a bottom support, a lamp strip switch, the earth, a connecting shaft, a celestial sphere, a lamp strip, a declination circle, a sky, a sky support and a lighting mechanism, the lamp strip switch is installed on the bottom support, the earth is fixed in the celestial sphere through the connecting shaft, and the connecting shaft is connected with the connecting shaft. According to the equipment for simulating the moving tracks of the sun at different latitudes and different time, the moving tracks of the sun at different latitude positions can be conveniently described on the sky, abstract problems are visualized, students can conveniently observe the moving tracks of the sun, the students can conveniently learn and understand the content of the sun apparent motion, and the teaching efficiency is improved. Students can conveniently transfer and draw a three-dimensionally presented annual solar apparent motion track into a graph, further understand abstract knowledge of solar apparent motion, and improve the cosmic view of a learning concept.

This device for determining coordinates of a low Earth orbit object is provided with: a narrow-field optical telescope (10) comprising a narrow-field image-forming optical system (11) that has a narrow viewing angle and high resolution, a narrow-field light selecting means (12) for selecting, from light concentrated by the narrow-field image-forming optical system (11), light coming from a low Earth orbit object, and a narrow-field image sensor (13) for outputting, as narrow-field image data, the light selected by the narrow-field light selecting means (12); a wide-field optical telescope (20) comprising a wide-field image-forming optical system (21) that has a wider viewing angle and lower resolution than those of the narrow-field image-forming optical system (11) and that is oriented in the same direction as an orientation direction of the narrow-field image-forming optical system (11), a wide-field light selecting means (12) for selecting, from light concentrated by the wide-field image-forming optical system (21), light coming from a star, and a wide-field image sensor (23) for outputting, as wide-field image data, the light selected by the wide-field light selecting means (22); and a low Earth orbit object position coordinate computation device (50) for identifying celestial sphere coordinates of the low Earth orbit object by using detected position coordinates of the low Earth orbit object detected from the narrow-field image data from the narrow-field image sensor (13) and detected position coordinates of the star detected from the wide-field image data from the wide-field image sensor (23).

This method (PREF) makes it possible to reference at least one artificial satellite (SAT) in a star catalog (CTG) comprising the position of at least one star projected onto a celestial sphere (SC). It comprises: - a step (E10) of obtaining coordinates of an observation location of said at least one artificial satellite (SAT) and orbital parameters (TLE) of said at least one artificial satellite (SAT); - a step (E50) of projecting the satellite (SAT) onto said celestial sphere (SC) according to a direction of view determined from said orbital parameters (TLE) and the observation location; - a step (E80) of recording, in said catalog (CTG), coordinates of the satellite (SAT) projected onto the celestial sphere (CS), the coordinates of the stars and of said at least one artificial satellite (SAT) being expressed in the same geocentric reference frame, called the star catalog reference frame. Fig. 3

The invention relates to a method for monitoring moving space objects, the method being implemented by a monitoring system (100), comprising the following steps: - sliding acquisition of at least one stack (12, 12') of image frames of space along a known trajectory on the celestial sphere, each stack of frames comprising at least three frames, each frame being recorded with an exposure time of less than 1 second, - detection, in the field of view, of a plurality of stars (14, 55), preferably several dozen, - estimation of the coordinates of the detected stars, - identification of the detected stars with a list of reference stars extracted from a stellar catalog, comprising several thousand reference stars, - establishment of a coordinate relation linking the celestial coordinates to the coordinates in the frames of the stars present in the list of reference stars, - detection of at least one moving space object (15,56) in at least one stack and estimation of their dated frame coordinates, - conversion of the dated frame coordinates of each detected moving space object into coordinates on the celestial sphere by the coordinate relation. Figure for abbreviation: [Fig. 1 ],

The present application relates to a kind of wide-field sky survey star catalogue construction method, device, medium and electronic equipment, comprising: the original image of the observed celestial body photographed is preprocessed, obtains the local star catalogue of single exposure of the original image;It is compared with standard star catalogue and is solved, obtains the conversion relationship from image pixel coordinate to celestial sphere coordinate and solving error;According to the morphological parameters of celestial body, the transformation rate matrix of the celestial sphere coordinate of celestial body, solving error and celestial body constructs observed covariance matrix under celestial sphere coordinate system, and the Mahalanobis distance of the matrix and position difference vector is calculated to determine that observed celestial body is target celestial body;After screening and merging calculation to the multiple observation data of target celestial body in a certain time period, the final coordinate, flow and error matrix of target celestial body are obtained.The present application utilizes covariance matrix to carry out matching and merging, avoids that the star point of elongated edge is mis-matched to adjacent celestial body, significantly reduces false positive rate and false negative rate.

The invention provides a near space aircraft refraction starlight guidance, optical axis maneuvering and intersection positioning method. Firstly, a starlight path differential equation in a near space is deduced, and then a starlight refraction distribution model under a refracted starlight coordinate system is established by using a numerical integration method. On the basis, determining the nadir distance pointed by the optimal optical axis of the star sensor according to the selected optimal refraction observation interval and the altitude of the aircraft as a guidance law, and deriving an optical axis longitudinal rotation angle as an optical axis maneuvering control instruction according to an attitude angle and an optical axis transverse rotation angle; an intersection point of an isorefraction line and an isoaltitude line of a single refraction star and an intersection point of a normal vector of refraction surfaces of two refraction stars and the isorefraction line are respectively utilized; positioning is achieved through four methods including the intersection point of the geocentric vector of the circle center of the inscribed circle of the spherical triangle intercepted by the refraction surfaces of the three refraction stars on the celestial sphere and the isorefraction line and the intersection point of the feature vector corresponding to the minimum feature value of the matrix constructed by the normal vectors of the refraction surfaces of the at least three refraction stars and the isorefraction line.

This invention provides an all-sky polarization sensing device and heading calculation method based on a curved surface biomimetic compound eye, relating to the fields of biomimetic navigation and optical sensing technology. The device includes: a curved substrate; several polarization imaging units fixedly arranged in a close-packed hexagonal array on the outer surface of the curved substrate; and a processing unit electrically connected to all polarization imaging units. The curved substrate includes first-level, second-level, and third-level sub-surfaces, each with a textured layer, forming a fractal moth-eye structure. The method employs an online self-calibration method based on field-of-view overlap constraints to correct the original image data acquired by each polarization imaging unit; maps all corrected image data to a virtual celestial coordinate system to generate an all-sky polarization angle distribution map; when some units are obstructed, the polarization information of the obstructed area is reconstructed using an interpolation algorithm, thereby calculating the absolute heading angle of the carrier. This invention achieves highly robust and high-precision all-weather autonomous navigation.

To provide a video management technology for creating a 3D point group of a space where structures are arranged in a wide range in a short time, and for highly accurately estimating the position of a photographing object.SOLUTION: The video management system 10 includes a first acquiring unit 21 that acquires an omnidirectional video image 15 captured by a first image-capturing part 11, a clipping unit 18 that clips a reference planar image 17 from a celestial sphere frame 16 in a designated azimuth 19 defined in a first coordinates system of the first image-capturing part 11, an extracting unit 25 that extracts a feature point 26 defined in the first coordinates system from the celestial sphere frame 16, a defining unit 27 that defines the same feature point 26 in a plurality of celestial sphere frames 16 as a 3D point cloud 23 in a second coordinates system and defines an image-capturing position 29 and posture information 37 of the first image-capturing part 11 that captures each celestial sphere frame 16 in the second coordinates system.SELECTED DRAWING: Figure 1

The star table partition method, system and terminal provided in the application divide the celestial sphere into 20x(N+1) 2 sub-regions, that is, the star table is divided into 20x(N+1) 2 sub-regions, wherein N [0, +infinity); an intersection equation of a star pointing and a sub-region of the celestial sphere is established; the intersection equation of the star pointing and the sub-region of the celestial sphere is solved; and stars corresponding to each sub-region of the celestial sphere are screened from the star table. The star table partition method, system and terminal provided in the application utilize a regular icosahedron inscribed in the celestial sphere to uniformly partition the celestial sphere, and improve the problem of uneven star table partition and low partition degree by adjusting parameters, and are easy to implement.

The present application relates to the technical field of intelligent driving, and discloses a starry sky projection method, device, equipment, medium and program product of a vehicle, real-time pose information of the vehicle is acquired, and real-time environment images around the vehicle are collected; a first observation direction based on the vehicle is determined based on the real-time pose information, and celestial body coordinate information of visible celestial bodies in a celestial coordinate system is determined according to the first observation direction; the superimposed positions of the visible celestial bodies in the real-time environment images are determined by using the celestial body coordinate information; the visual features of the visible celestial bodies are rendered to the superimposed positions, an augmented reality picture is obtained, and the augmented reality picture is displayed through a display component of the vehicle. The present application calculates the corresponding positions of the visible celestial bodies in the screen by fusing the real-time pose and the real scene images of the vehicle, and the visible celestial bodies are superimposed in real time to the real scene picture outside the vehicle, so that the user can obtain stable and high-precision starry sky augmented reality navigation on the vehicle display component without holding a device.

To provide an electromagnetic wave information processor for effectively and inexpensively projecting the measurement and estimation information of electromagnetic waves distributed in all the directions of the earth and cosmic space to the whole celestial sphere and the whole earth surface.SOLUTION: An input unit that inputs a measurement result from a measurement unit that measures electromagnetic waves incident on a spacecraft from substantially all directions, a calculation unit that performs calculation on the basis of information input to the input unit, and an output unit that outputs a calculation result in the calculation unit, the calculation section calculates, on the basis of the measurement result input to the input section, a local omnidirectional feature value that is a coefficient of a local basis function indicating a distribution of the electromagnetic wave input by the input section in a spacecraft coordinate system centered on the spacecraft at a predetermined position in space, and calculates, on the basis of a plurality of local omnidirectional feature values and information concerning a plurality of predetermined positions in space, a whole omnidirectional feature value that is a coefficient of a whole basis function to create a map indicating a distribution of a whole electromagnetic wave source including the earth's surface and the space.SELECTED DRAWING: Figure 5

This invention discloses a method and system for detecting low-Earth orbit satellite orbit changes based on stellar background. The method includes: defining a coordinate system, including a geocentric coordinate system, a celestial inertial coordinate system, and a star sensor coordinate system; acquiring star point images through a star sensor, obtaining a stellar database and a satellite ephemeris database; calculating the correspondence between each star point in the star point image and the stellar and satellite ephemeris databases using a triangulation matching algorithm within the coordinate system, and identifying stellar and satellite star points; using the identified stellar star points as a reference, calculating the satellite's spatial position based on the satellite star point's trajectory in the star point image and historical ephemeris data in the satellite ephemeris database, and comparing this position with the predicted spatial position based on historical ephemeris data to determine whether a satellite orbit change has occurred. This invention offers low detection cost, convenient execution of the detection task, and strong autonomy and anti-interference capabilities.